DESCRIPTION: The basic goal of the work is to understand the factors affecting interfacial and transmembrane charge transfer in lipid bilayers. The work is potentially important, since the maintenance of ion gradients across membranes is one of the defining qualities of living systems. The approach characteristic of this work is the use of photoinduced transfer of electrons across lipid bilayers. This permits the study of internal electrostatic effects. In one phase of the work, it is proposed to apply this method to voltage gated ion channels, as an effort to gain photo-control over channel activity. The extension of the method to nerve cells is a possible direction of the research. A second avenue involves the further study and development of a device for electrostatic ion pumping that was created in Dr. Mauzerall's laboratory. Again, the ions are driven across the membrane by photoinduced charge transfer across an interface. This device allows the accurate calibration of electrostatic effects in transmembrane phenomena. The third project involves the determination of parameters of the biological ion pumps bacteriorhodopsin which pumps protons, and halorhodopsin which pumps chloride ions. The enthalpy and volume changes are associated with various steps undergone by these photoinduced pumps. These experiments will involve photoacoustic spectroscopy, a specialty of Dr. Mauzerall.